The origin of the Koloss is a subject of debate among many historians. Some claim that they appeared from the mountains, while others claim that they were created by a man that became a deity for a short time. Most people claim Koloss don't even exist. Regardless, they are more than a force to be reckoned with. What they lack in skill and intellect they make up for brute strength. There is no easy way to kill a Koloss, and their large blunt "swords" are too large to be wielded by anyone of equal size.

Koloss range from 5 feet to 12 feet, their size normally an indication of their age. By the time a Koloss reaches 12 feet tall, they typically die of heart failure, though there are some unique cases where a Koloss may grow up to 14 or even 15 feet tall. Female Koloss do not exist, or at least have not been found. For this reason, their method of reproduction is a gruesome secret that none outside of their ranks know.

Koloss are instantly recognizable by their pale bluish skin, which has been nailed to their anatomy by large metal spikes. This skin fits a young Koloss nearly perfectly, however as the Koloss grows, the skin does not. It begins to stretch and tear, exposing raw muscle that should otherwise be covered. Older Koloss are unable to speak coherently for this reason, since they are unable to use their lips to form words.

While Koloss may seem to be nothing more than savage animals, they do have a small manner of intelligence. They can speak, though when they do speak, they sound very deliberate in their word choice, as if carefully forming each word in their mind. They cannot read or write, and no attempt has been made to teach them.

Koloss have no special tactics, they attribute skill and strength with size, and so they will often charge smaller enemies, while giving respect to larger enemies. Once enraged however, the Koloss will never retreat. Their abilities are very similar to that of a Barbarian, making every engagement a lengthy fight to the death.

Immune to Enchantment: Koloss cannot be affected by spells such as charm person, or fascinate. Any attempt to control how they think or act will be shrugged off. However, the player may still attempt to cast the spell. The DM tells the player to roll d20 against spell resistance, however, only a natural 20 will actually be successful. In the case of a natural 20, the player gains permanent control of the Koloss. The player may then control every action of the Koloss, or just give it basic commands. The control is always active, whether or not the player is conscious, and even over great distances.

Greater Rage: 3 times per day, an Adult Koloss may fly into a blood frenzy, adding +6 to his Strength and Constitution Ability scores, as well as adding +7 to his Will save. As an effect of the Blood Rage, the Koloss also takes a -2 penalty to AC. This effect lasts for 13 rounds. His stats return to normal after the frenzy has passed.

Improved Uncanny Dodge: The Koloss have no known weak point to exploit, and are always expecting a fight, for this reason, it is extremely difficult to catch them flat-footed, and it is nearly impossible to sneak attack them. Only a Rogue of 15 HD or more may sneak attack an Adult Koloss.